Airbag Module for Protection of a Vehicle Occupant

ABSTRACT

An airbag module for protecting a vehicle occupant is provided. The airbag module comprises at least one airbag. A gas generator is in fluid communication with the airbag to inflate the airbag with a gas. A deformable ribbon interfaces with the fluid communication between the gas generator and the airbag. The deformable ribbon has a spiral form with a first radial end covering a second radial end when the gas generator is deactivated.

The invention relates to an airbag module for protection of a vehicle occupant according to the introductory section of patent claim 1.

Safety systems are known which are intended to protect a person sitting in a motor vehicle in the case of a sudden deceleration of the travel movement, as the person sitting in the vehicle is flung contrary to the deceleration movement against a base located in the vehicle, for example the instrument panel, the front seat, the side wall etc. Without the named safety systems, this often leads to serious injuries of the vehicle occupant(s), as then no adequate protection is present in particular for the head and the thorax of the vehicle occupants.

Such safety systems particularly include safety belts and airbag devices. An airbag device, as is known, comprises an inflatable airbag, which is accommodated for example, in the steering wheel hub cover, in the instrument panel and/or in the side wall cladding of the motor vehicle. In case of collision of the vehicle against a fixed resistance, an acceleration sensor activates a gas generator, which is ignited within an extremely short time and inflates the airbag with filling gas. For this purposed, the cover or the cladding tears open at a defined point and frees the path for the airbag which is filling with gas. The affected person then sinks into the airbag, which considerably decreases the load which occurs during the sudden deceleration of the vehicle movement.

An airbag device is known from U.S. Pat. No. 4,966,388 in which an airbag is accommodated in a side door to the side of a vehicle occupant, whereby the airbag is inflated by a gas generator when a side collision occurs, so that the inflated airbag takes up a space between the side door of the vehicle and the vehicle occupant. A disadvantage of this airbag system is that the gas which is issuing from the gas generator is very hot, which means that it can damage the airbag or even set it alight, and can injure the vehicle occupants.

A flame protection device is known from U.S. Pat. No. 6,419,266 B, in which the airbag is folded together at the gas generator at the beginning. The device also includes a deflector for accommodation and deflection of the hot gases of the gas generator. This deflector consists of a single expandable metal ribbon, which is located between the gas generator and the airbag. This metal ribbon exhibits a tubular form with a closed circumferential jacket. When the gas generator is activated, the gas is transported into the airbag after it has passed the deflector through side openings in said deflector. As the metal ribbon of the deflector is folded together in several layers before activation of the gas generator, it is difficult to mount. In addition, its tubular form means that it is more complicated and more expensive to manufacture.

The invention is based on the task of creating an airbag module of the type named at the beginning which is as far as possible non-inflammable and which is also easy and inexpensive to manufacture and mount.

The invention is based on the recognition that the heat which occurs when the gas suddenly leaves the gas generator can damage the airbag and can injure the vehicle occupant and therefore the heat which is generated has to be effectively captured before it reaches the airbag.

The task which is set is solved in accordance with the characteristics of the main claim by means of an airbag module in which the expandable gas deflection device is designed in the form of a deformable ribbon, which exhibits a spiral form in cross section, whereby the radial ends of the ribbon cover each other when the gas generator is deactivated.

According to this, the deformable ribbon does not have a closed tubular form, as the free longitudinal edges of the ribbon overlap. This means that the ribbon which serves as a deflector for the gas which emerges from the gas generator can be manufactured and mounted more easily. The spiral form can also be implemented by means of two cylinder segments which overlap one another as regards their circumference.

According to one form of the object of the invention, the deformable ribbon surrounds the gas generator placed in the airbag as regards the circumference, if the airbag module or the gas generator are in non-activated state, so that the free longitudinal edges, seen in cross section, cover the radial ends of the ribbon.

Furthermore, the deformable ribbon is formed in such a way that when the gas generator is activated, the issuing gas unfolds the spiral form of the deformable ribbon to blow up the airbag, and this ribbon lies against the inner walls of the airbag under the pressure of the gas. This means that the free longitudinal edges of the deformable ribbon flap away from the gas generator and towards the airbag, whereby the diameter of the spiral form is increased.

As the deformable ribbon is preferably made of a flexible and heat resistant plastic or metal material, the gas which is hot because of the ignition in the gas generator first strikes the ribbon, which absorbs a part of the heat and energy of the gas. Extremely hot gas can therefore no longer be conveyed into the airbag to be inflated. This means that damage to the airbag and risk of injury to the vehicle occupants to be protected, in particular by the effects of heat, is avoided.

According to a further form of the airbag module according to the invention, a further airbag can be located between the deformable ribbon and the airbag, which is connected with the outer airbag and the gas generator from the point of view of flow. In the case of this variant, the deformable ribbon opens until it lies against the inner walls of the inner airbag. In this process, further heat energy is absorbed by the inner airbag, and the effect of the heat of the gas is reduced immediately following exit from the gas generator.

Furthermore, when the gas generator is activated, the circumference of the deformable ribbon is limited by its own dimensions and/or by the walls of the surrounding airbag.

Although the radial ends of the spiral-shaped ribbon are open for the exit of the gas, it can be useful if the deformable ribbon exhibits at least one gas outflow opening on its circumference. This is particularly useful if a further inner airbag is not present, e.g. in the case of so-called curtain-type window airbags, in which the gas is intended to exit into the airbag rapidly and over as large and area as possible.

Also such an airbag of a window airbag can, for example, exhibit at least one seam directed towards the circumference of the deformable ribbon. This then serves for defined limitation of the expansion of the deformable ribbon following activation of the gas generator.

Finally it is provided that the gas generator, the airbag or the airbags and the deformable ribbon are connected to each other in fixed fashion at least one point. The airbag module itself is, for example, fixed to a roof or window rail, in a steering wheel bowl or the instrument panel of the motor vehicle.

In the following text, the invention will be described in more detail in several embodiments, using the attached drawings.

The drawings are as follows:

FIG. 1 a schematic side view of the airbag module according to the invention, arranged in a motor vehicle, in a first embodiment with an outer and an inner airbag,

FIG. 2 a cross-section view of the airbag module according to FIG. 1 and

FIG. 3 a schematic side view of the airbag module in a second embodiment with only one airbag.

The airbag module 1 shown in FIG. 1 is fixed to a base, for example a side window rail 2 of a motor vehicle, using known fixing elements such as stay bolts and fixing screws. Furthermore, airbag module 1 comprises an outer airbag 4 and a smaller inner airbag 5 placed inside this, made of textile material. Inner airbag 5 surrounds an expandable gas deflector device 6, which is designed in the form of a deformable ribbon 7. Gas deflector device 6, for its part, winds round a gas generator 8, which exhibits a large number of gas exit openings 9 distributed on the circumference.

Deformable ribbon 7 consists of a flexible and heat-resistant plastic or metal material and has a spiral form according to FIG. 2 seen in cross-section, whereby the radial ends of ribbon 7 cover each other radially and axially when gas generator 8 is in deactivated state.

On activation of gas generator 8, the issuing gas unfolds the spiral form of deformable ribbon 7 and, under the pressure of the gas, takes on the form and position shown by the dash-dot-dash line shown in FIG. 2. At the same time, the gas also flows out via the radial ends of ribbon 7. In this process, unfolded ribbon 7 comes to lie against the inner wall of inner airbag 5, now suddenly inflating.

The circumference of deformable ribbon 7 is therefore limited by the walls of the surrounding inner airbag 5. If inner airbag 5 exhibits a larger volume, the enlarging circumference of deformable ribbon 7 is itself limited by its expansion. The gas, which is still under pressure, continues to enter the interior of outer airbag 4 gas through flow openings 10 inserted in inner airbag 5 and shown in schematic form, and also expands outer airbag suddenly. This state of the airbag module is shown in FIG. 2.

As can also be seen from FIG. 2, gas generator 8, inner airbag 5, and if this is not connected to the latter, also outer airbag 4 as well as deformable ribbon 7 are connected to each other in fixed fashion at a central point, for example by means of a screw connection 11. If appropriate, a support 12 is provided for stabilising the connection. In the simplest case, this arrangement is fixed in the container of this airbag device.

In the case of the embodiment according to FIG. 3, only one airbag 4 is present, which here is in the form of a side airbag. Airbag 4 and gas generator 8 are connected with the container of the airbag device by means of screw fixing 13 and a fixing clip 14, which is fixed to the side window rail 2 of the motor vehicle, or is connected directly with side window rail 2. If the device is in the form of a window airbag, the fixing of airbag 4 and of the gas generator would be implemented on the roof frame of the vehicle.

Gas generator 8 is wound round at least in part by deformable ribbon 7, in fact in a similar way as shown in FIG. 2 and described above. On the circumference side, ribbon 7 possesses at least one gas outflow opening 15 for further direction of the gas streaming off from gas generator 8 into airbag 4.

Airbag 4 exhibits two T-shaped seams 16 at a distance to one another. When spiral-shaped ribbon 7 unfolds, its circumference expands to the extent that it reaches T-shaped seams 16. Then the gas which continues to flow out at the radial ends and at gas outflow opening 15 from gas generator 8 ensures complete inflation of airbag 4.

According to the embodiment according to FIG. 1, gas generator 8 can be located inside the space which is created by spiral-shaped ribbon 7. According to the embodiment shown in FIG. 3, this gas generator can be located in part inside this space. However, a third embodiment is also possible, according to which gas generator 8 is completely outside ribbon 7 and the airbag. In this case, the gas generator is provided with a connection piece or is connected with a gas lance, which directs the gas from the gas generator into the inside of the space formed by spiral-shaped ribbon 7.

LIST OF REFERENCE NUMBERS

-   -   1 Airbag module     -   2 Side window rail     -   3 Fixing element     -   4 Outer airbag     -   5 Inner airbag     -   6 Gas deflector device     -   7 Deformable ribbon     -   8 Gas generator     -   9 Gas exit opening     -   10 Gas throughflow opening     -   11 Screw connection     -   12 Support     -   13 Screw fixing     -   14 Fixing clip     -   15 Gas outflow opening     -   16 Seam 

1. An airbag module for protection of a vehicle occupant, the airbag module comprising: at least one airbag; a gas generator, in fluid communication with the airbag to inflate the airbag with a gas; and deformable ribbon interfacing with the fluid communication between the gas generator and the airbag, wherein the deformable ribbon has a spiral form with a first radial end covering a second radial end when the gas generator is in a deactivated state and an unfold form with the first and second radial ends extending outwardly in correspondingly different directions when the gas generator is in an activated state.
 2. The airbag module according to claim 1 wherein both the gas generator and the deformable ribbon are disposed within the airbag, and the deformable ribbon surrounds the gas generator.
 3. Airbag module according to claim 2 wherein the deformable ribbon is configured to unfold the spiral form to lie against innerwalls of the airbag when the gas generator is activated and the gas flows out under pressure.
 4. Airbag module according to claim 1 wherein the deformable ribbon is a flexible plastic or metal material.
 5. Airbag module according to claim 2 further comprising a second airbag disposed between the deformable ribbon and the airbag and in fluid communication with the airbag and gas generator.
 6. The airbag module according to claim 3 wherein when the gas generator is activated unfolding of the deformable ribbon is circumferencely limited by one of dimensions of the deformable ribbon or by the inner walls of the airbag.
 7. The airbag module according to claim 1 wherein the deformable ribbon defines at least one gas exit opening.
 8. The airbag module according to claim 3 wherein the airbag includes at least one seam disposed towards the the deformable ribbon (7) that limits the unfolding of the deformable ribbon.
 9. The airbag module according to claim 1 wherein the gas generator, the airbag and the deformable ribbon are fixedly connected together about at least one point.
 10. The airbag module according to claim 1 wherein the deformable ribbon includes two cylinder segments which circumferencely overlap. 